Dental casting apparatus.



H. V. HART.

DENTAL CASTING APPARATUS.

APPLIOATION FILED DEC, 8, 1913,

L, 1 05,425. Patented July 28, 1914.

2 SHEETS'fiBEET 1.

H. V. HART.

DENTAL CASTING APPARATUS. APPLIOATION TILED 1120.8.1013.

Patented July 28, 1914.

2 SAiB-ETS SHEET 2.

1717 Vw/(u' Haw/ 731 12113;

10172263 sea y. M an HARRY v. near, or QUINCY, ILLINOIS.

DENTAL CASTING APPARATUS.

1 Specification of Letters Patent.

Patented July 28, 1914.

Application filed December 8, 1913. Serial No. 805,263.

To all whom it may concern:

Be it known that I, HARRY V. HART, a citizen of the United States, residing at Quincy, in the county of Adams and State of Illinois, have invented certain new and useful Improvements in Dental Casting Apparatus, of which the following is a specification.

Tliis invention relates to an apparatus for casting dental fillings of the character known as inlay fillings and the like, the object of the invention being to provide a casting apparatus which will combine in a single structure th'e principles of the vacuum inlay and steam pressure machines, and give in a single joperation a forcing pressure upon the liquid gold or other material from which the casting is to be made, so that the metal will conform in the most accurate degree t'o the mold cavity and produce a very dense or solid and accurately shaped casting.

A further object of the invention is to provide acasting apparatus embodying a mold or flask, a vacuum pump, and a manually operable steam generating and pressure producing element, together with a valve mechanism'automatically operated by the movement of the steam generating pressure ele ment to operative position to open communication between the mold or flask and the vacuum pump, Which in a single operation will produce a suction on one side of the molten metal and a positive pressure on the other side thereof to force the molten metal into the mold cavity.

With these and other objects in View, the invention consists of the features of construction, combination and arrangement of parts hereinafter fully described and claimed,

reference being had to the accompanying drawings, in which F igalre 1 is a side elevation of a-castin flPPd'JillllllS constructed in accordance wit my invention, showing the pressure producing device in operative position upon the mold or flask, and with the valve controlling mechanism in valve opening position; Fig. 2 is a vertical transverse section on the line 22 in Fig. 1; Fig. 3 is a horizontal transverse section on the line 3-3 in Fig. 1; Fig. 4 is a sectional side elevation showing the pressure producing device thrown back to an inoperative position and the valve closed to cut off communication between the mold or flask and the vacuum pump; and Fig. 5 is a vertical longitudinal section through the ports, arranged as shown in Fig. 1, and illustrailing the operation of the device in making a casting.

As is well known, fillings of the character described are made by first forming :1 pattern from wax, which pattern is formed directly in the cavity to be filled, after which the wax pattern is placed, with other proper forming elements, in a body of investment material and contained within a flask or mold. The flask and body of investment material are then heated, by which a portion of the wax is eva orated and the remainder liquefied and ta en up by the pores of the investment material, after which the other pattern forming elements are removed, thereby roducing in the body of investment material a mold cavity, a cup or chamber above the same for the reception of the gold or other metal and a conducting sprue 0r passage leading downward from thidchamber to the cavity for the flow of the go After the mold is made in the manner described a mass of metal of suitable size to form the desired casting is placed in the metal chamber and then, by suitable means,

the mold is heated to a sutliciently intense degree to melt the metal. Owing to the small size of the sprue or passage, this molten metal cannot flow down into the cavity,

and to cause its flow into the cavity it has been heretofore the practice to either draw the molten metal into the cavity by suction under the action of a vacuum apparatus, or to positively force the gold from the chamher through the sprue and into the cavity by suitable pressure from above, such as steam pressure. In many cases it is found that it is impossible to secure the roper degree of suction or forcing pressure in order to make very dense and fine castings; and one object of my invention is to provide a means by which this diiliculty may be overcome in a simple and effective manner and by means: of which the two principles of inducin the gold to flow into the cavlty may be com ined in a single apparatus.

The invention is also designed to provide a means whereby,lwhen the steam pressure element is ad usted to an operative position, communication will also be established be tween the mold and the vacuum appliance.

In carrying my 'invention'into practice Iv provide a suitable type of vacuum appliance, such as a vacuum pump 1, with which communicates a nipplefl supportingan an; nularly grooved plate 3adapted toreqe'ive the lower edge of the moldQr flask 4=. The portion of the plate which lies beneath the is provi dedwith perforations 5 for estatnslimg' communication between the flask and passage in as nipple; As shown,

the said passage in the nipple is controlled "-byei valve-'6, whichis preferably of the rotaryftapered plu' type,.and is adapted, when turnedto di erent positions, to open and close the conducting passage, Supported; by the .plateB is a-bracket arm to which is pivotally' connected, as at 8, amanually operabler member 9. This-member is provided with a suitable grip or handle 10, and

- bested-12.

Ill!

with acup llto contain a charge bf a steam generating material, such as' a body of as- I The bracket arm'is' recessed to forma stop shoulder 13, and the pivoted end ofithe pressure generatingelement'is rovided with a stop projection: 14 adapts to engage the-shoulder 13 to limit the outward movement of'the: part 9 to an inoperative position.- The-mold orfiask 4: contains the body'of investment orother porous material 15 in which the mold I cavity 16, sprue or :passage 17 and chamber ldto-receivethe bo'dy-ofmetal 19'areformed, and it will be understood that the moldor flash is placed in position upon the plate 3 after it has been heated to reduce the metal to a molten state.

'WhileEthe; mold is being heated a vacuum Y fa suitable degree is formed in the'oylinder of the vacuum appliance 1 by operating the piston thereof, and the pressureproducing the water-saturated body of, asbestos be- 46 element '9 is prepared for use by saturating the body of asbestos 12 with water, The

I apparatus having thus'be'en primed for 0P1 eration and the mold or flask set in position,

th element 9 ismoved. downward so that the. cup -.11 will, be disposed in position; to: cover the top of the mold,

ing 'ther'eby brought into, the zone or the intenseheat of the mold, by -which the water'is' generated 'intosteam, producing pressure on the body-of metal 19 to force it downward from'the chamber-through the sprite or passage 17 into the mold cavityyld At thesame timethat the steam pressure is generated the valve 6 moved to establish communication between the mold cavity and vacuum aJpplianoaby-which a suction will be induced within the-cavity and throughout the body of investment material to draw the gold down into the cavity, the gold be- :ing-thu's subjected to adrawing action on one and a forcing pressure on its other forced downward, the valve W1 incense will be produced. For the purpose of insuring an accurate opening movement oi the valve. when the pressure producing ele ment 9 is" turned down to an. operative position, suitable connections between said pressure producing element and the valve are employed,fthe connections shown consisting in the present instance of a crank arm 20 connected with the stem of the valve and coupled by a link'2l to a crank member or projection on the member 9', whereby, when the pressure producin device is be opened and when the pressure producing device is moved upward or thrown backward, the

valve will be closed. An absolute certainty of'co-action between the vacuum producing and steam generating parts of the appliance .is thus insured, so that the operation may be carried out with the highest'degree of efliciency.

a It will be evident from the foregoing description that my invention provides an apparatus of the character described which is adapted in a simple,'reliable, convenient and efiicient manner to enable a dentist or 0 erator to simultaneously subject the mo ten metal to what may be termed two feeding and forcing pressures, that resulting from a drawingor suction action on one side, and that resulting from the steam forcing pressure on theother side, and that by this means material advantages over the ordinary processes may be obtained. It will, of course, be understood that the invention may be embodied in an organization employing any suitable construction of vacuum producing appliance and steam. pressure generating devices, or that the novel features of the inven ,tion may be applied to existing types of inlay or casting machmcs. Having thus described my invention, 1 claim:

. 1. An apparatus of the character described I embodying a vacuum producing appliance, a mold communicating therewith, a controlling valve in the line of communication, a

steam pressure producing element adapted to be disposed-over the mold. so as to be heat- .ed therefrom, and a connecting means bewith the mold,and connecting means between said element and the valve for open mg the valve when said element is disposed Upon the mold and elosh'lg', the valve when sa'ni element ia moved away ll-om the mohl.

3. A (lie! m1 inla v or casting appa 'alns eo1npri:-:'in;;' a vacuum pump, a mold support, a molil ailapiuil to he mounted upon said support; and plan-ml in communication with the vacuum pump, a controlling valve in the line of commonii-ation, a pivotally mounted pressure producing: element) having a onp for the reception of a material adapted to absorb moisture, sa'nl cup being); movable (lOWIl upon. (he 1nol l so that the aaiil mate rial will be subjected to the heat of the Inohl for the generation of steam pressure, and Valve controlling mains operated upon Lho .movenwnt of said element toward and from the mold to open and close the valve.

4'. i dental inlay or easting appm'atna eomprising a vacuum pump, a nipple rising tl'iei'efrom, a valve controlling the passage in N"; we

said nipple, opiate mounted, on the nipple, a lUUlll. adapted to rest, upon said plate and to eonm'nmicaio with the vacuum pump through the nipple, a nuanher pivotally mounted al'nlv provided one a ehamher nonliaining a body of moisture ahsorhin; material, saiilv member being movable (iown upon the mold to bring the moisture ahaorhing material info contact with ihe mohl for the generation of steam, crank elements, eonncoleil with the valve and pivotaily mounted lllLl'IllJQt', and a link oonnerting sai l eranlc: elements.

in testimony whereof I aliix my aignatnro in presenm: of two wiineeses.

MARE 1' V. llAfli'l",

"rHiIIICSSU-"Q illaaoannir 'lnmoao, JOHN F. Giannini. 

